Badcaps.net Forum
Go Back   Badcaps Forums > Troubleshooting Hardware & Devices and Electronics Theory > Troubleshooting Computer Displays
Register FAQ Calendar Search Today's Posts Mark Forums Read

 
Thread Tools Display Modes
Old 04-21-2020, 11:36 PM   #1
Drith
New Member
 
Join Date: Apr 2020
City & State: Chicago, IL
My Country: USA
I'm a: Knowledge Seeker
Posts: 6
Default DELL U2311Hb (E162032 Vol 3) Goes Black After 2 Seconds

Hello! I have a DELL U2311Hb monitor (mfg. May 2010) that will show a regular picture for 2 seconds and then go dark. The green power light stays lit but the screen is black and the menu buttons do not function. The power supply board says it is E162032 Vol 3. I looked at all the capacitors and they seem visibly fine.

I tried testing each of the radial capacitors with a regular multimeter's resistance meter set to around 20k. I watched signal build on them (some of them I had to turn up the measurement to 2000 because they'd slow down and get stuck). All of them eventually went to infinity except one: C765. It settled in the middle and even when I set my multimeter to diode it would not go to infinity.

My plan was to de-solder all the brown/black/green caps and buy new ones from Digi-Key to put on. Is there a better place to buy them from? One I found to replace C765 (220uf 25V) was this one. Does it look like a good choice?

Should I buy an ESR Meter, and if so which one? I saw this LCR-T4 Mega328 on eBay for $9. Is it any good for testing bad capacitors?

Any assistance would be most appreciated!
Attached Images
File Type: jpg IMG_9496_3000px.jpg (1.27 MB, 24 views)
File Type: jpg IMG_9497_3000px.JPG (1.81 MB, 16 views)
File Type: jpg IMG_9501_3000px.JPG (1.67 MB, 16 views)
File Type: jpg IMG_9507_3000px_rot.jpg (956.1 KB, 22 views)

Last edited by Drith; 04-21-2020 at 11:38 PM..
Drith is offline   Reply With Quote
Old 04-23-2020, 01:13 PM   #2
Drith
New Member
 
Join Date: Apr 2020
City & State: Chicago, IL
My Country: USA
I'm a: Knowledge Seeker
Posts: 6
Default Re: DELL U2311Hb (E162032 Vol 3) Goes Black After 2 Seconds

I tested all the resistors, the fuse, and the transistor and they seem good.
Drith is offline   Reply With Quote
Old 04-24-2020, 05:45 AM   #3
Drith
New Member
 
Join Date: Apr 2020
City & State: Chicago, IL
My Country: USA
I'm a: Knowledge Seeker
Posts: 6
Default Re: DELL U2311Hb (E162032 Vol 3) Goes Black After 2 Seconds

I removed C765 and tested it with the multimeter. Now that it's removed from the board, it seems to test properly and when I set to measure 20k Ohm the resistance gradually rises and then goes to infinity just as the other caps do.

The board has a dozen caps. Should I buy replacements for all of them and try that, or is the problem likely somewhere else given they seem to test fine and they don't look visibly damaged?
Drith is offline   Reply With Quote
Old 04-30-2020, 07:07 PM   #4
CapLeaker
Leaking Member
 
CapLeaker's Avatar
 
Join Date: Dec 2014
City & State: Atlantic Canada
My Country: Canada
Line Voltage: Ground, 0Hz
I'm a: Hobbyist Tech
Posts: 4,504
Default Re: DELL U2311Hb (E162032 Vol 3) Goes Black After 2 Seconds

Could be anything, from bad solder joints, bad capacitors, transformer going bad, bad connection somewhere...
You can’t check the health of a capacitor, by charging it up with your DMM in ohms mode and watch it climb. Only because they “look” good, doesn’t mean that they are good either. If you want to check caps you have to invest into an LCR or ESR meter.
CapLeaker is offline   Reply With Quote
Old 05-01-2020, 06:32 PM   #5
R_J
Badcaps Veteran
 
Join Date: Jun 2012
City & State: ☻
My Country: Canada
I'm a: Professional Tech
Posts: 6,190
Default Re: DELL U2311Hb (E162032 Vol 3) Goes Black After 2 Seconds

Check the voltages on the plug to the main board and see if they remain when the moniitor blanks out. I would suspect one of the ccfl's has an issue, either bad/broken ccfl or broken ccfl lead.

You may have a bad ccfl in the panel, there are 4 ccfl's, 1,2,3,4 so unplug 2,3,4 and see if you get a flash of backlight from ccfl #1 (this may be fairly dim) If you do see a flash of the backlight, unplug 1,3,4 and try again with #2, trying each ccfl by itself should confirm they are working or not. In some cases the wire on the ccfl breaks and that is all that is wrong.

Last edited by R_J; 05-01-2020 at 06:42 PM..
R_J is offline   Reply With Quote
Old 05-03-2020, 08:08 AM   #6
MeinFreund
New Member
 
Join Date: Oct 2013
City & State: Bavaria
My Country: Germany
I'm a: Knowledge Seeker
Posts: 9
Default Re: DELL U2311Hb (E162032 Vol 3) Goes Black After 2 Seconds

I know its a different DELL model, but it sounds similar to the problem described here:
https://www.badcaps.net/forum/showth...699#post663699
MeinFreund is offline   Reply With Quote
Old 05-04-2020, 02:50 PM   #7
Drith
New Member
 
Join Date: Apr 2020
City & State: Chicago, IL
My Country: USA
I'm a: Knowledge Seeker
Posts: 6
Default Re: DELL U2311Hb (E162032 Vol 3) Goes Black After 2 Seconds

Thank you all sincerely for the replies! To aid searching and such, the power board says it is 4H.14W02.AF0.

Quote:
Originally Posted by CapLeaker View Post
Could be anything, from bad solder joints, bad capacitors, transformer going bad, bad connection somewhere...
You can’t check the health of a capacitor, by charging it up with your DMM in ohms mode and watch it climb. Only because they “look” good, doesn’t mean that they are good either. If you want to check caps you have to invest into an LCR or ESR meter.
You make a good point that without narrowing it down, and without an obvious issue from visual inspection, the issue could be anywhere and so I should focus on narrowing down the issue. Is there a budget LCR/ESR meter you might be able to recommend? Is the LCR-T4 Mega328 sufficient?

Quote:
Originally Posted by R_J View Post
Check the voltages on the plug to the main board and see if they remain when the moniitor blanks out. I would suspect one of the ccfl's has an issue, either bad/broken ccfl or broken ccfl lead.

You may have a bad ccfl in the panel, there are 4 ccfl's, 1,2,3,4 so unplug 2,3,4 and see if you get a flash of backlight from ccfl #1 (this may be fairly dim) If you do see a flash of the backlight, unplug 1,3,4 and try again with #2, trying each ccfl by itself should confirm they are working or not. In some cases the wire on the ccfl breaks and that is all that is wrong.
I did the flashlight test and can see the silhouetted picture! However, now the monitor does not flicker on at all. The blue power led switch lights, the set stays black, but I can see a silhouette with the flashlight. Does that mean the issue is likely the CCFLs or the power supply going to the CCFLs, and so not the main board?

I tried disconnecting the four cables running to the panel leaving one plugged in at a time but it did not seem to have any effect. I could still see the silhouetted picture, but no backlight. I then tried having them all plugged in except one and it had no effect either.

I tested the voltages to the main board as follows. When the monitor is turned off, the 3rd pin that read 2.5 drops down to 0.02 and the fourth that read 0.65 drops to 0.12. The rest of the voltages stay the same whether the monitor is on or off.



Quote:
Originally Posted by MeinFreund View Post
I know its a different DELL model, but it sounds similar to the problem described here:
https://www.badcaps.net/forum/showth...699#post663699
I have checked over the threads and their monitor seems to be significantly different than mine. I don't see the transformer array or backlight tubes on mine, at least not in the same place. I attached full pictures of the monitor's guts.
Attached Images
File Type: jpg IMG_9515.JPG (859.8 KB, 6 views)
File Type: jpg IMG_9519.JPG (1.35 MB, 5 views)
File Type: jpg voltages.JPG (194.7 KB, 47 views)

Last edited by Drith; 05-04-2020 at 02:52 PM..
Drith is offline   Reply With Quote
Old 05-18-2020, 02:50 PM   #8
Drith
New Member
 
Join Date: Apr 2020
City & State: Chicago, IL
My Country: USA
I'm a: Knowledge Seeker
Posts: 6
Default Re: DELL U2311Hb (E162032 Vol 3) Goes Black After 2 Seconds

What other tests or process can I go through to determine what is wrong? If it's the CCFLs that are burnt out, it looks like I could buy an LED replacement for pretty cheap but I'm not sure how to determine if that's the issue. Or if the power supply board is the issue, how can I check that?
Drith is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump



Badcaps.net Technical Forums 2003 - 2020
Powered by vBulletin ®
Copyright ©2000 - 2020, Jelsoft Enterprises Ltd.
All times are GMT -6. The time now is 12:01 PM.
Did you find this forum helpful?